Before You Start
Information on this page relates to Ubuntu-supplied and -supported builds of the Mozilla Firefox browser, i.e. the firefox package in the Ubuntu repositories. It assumes the use of the package management tools to install or update plugins. If you are using other, unsupported versions of Mozilla Firefox and would like to install or update plugins, see the Mozilla Browser Plugin Support Documentation.
You must have administrative privileges to install packages.
Make sure you have enabled the Universe and Multiverse repositories. See Managing Repositories with Ubuntu or Kubuntu for help with this.
See Installing Software for help with installing packages.
Flash
For instructions on how to install the Flash plugin, see the Flash section on the Restricted Formats page.
Java
For instructions on how to install the Java plugin for Firefox, see Java.
Adobe Reader
For instructions on how to install Adobe Reader plugin for Firefox, see the Adobe Reader wiki page.
Real Player
For instructions on how to install the Real Player plugin for Firefox, see the RealPlayer page.
Totem Plugin
Totem, Ubuntu's default video player, supports both the gstreamer (default) and xine multimedia frameworks.
On 6.06 LTS (Dapper), the plugin depends on the multimedia framework you use. If you use totem-gstreamer (the version of Totem that uses the gstreamer back-end), install the totem-gstreamer-firefox-plugin package. If you use totem-xine, you should install the totem-xine-firefox-plugin package.
On 6.10 (Edgy), simply install the totem-mozilla package.
Note: The current version of the Totem plugin that handles real media files is not functional. To make RealPlayer take over the handling of real media files, follow the instructions in the RealPlayer and Firefox 2 section on the RealPlayer wiki page.
MPlayer Plugin
The MPlayer media player is not installed by default on Ubuntu Linux. For 6.06 LTS (Dapper) and 6.10 (Edgy), simply install the mplayer package from the multiverse repositories. For users of 5.10 (Breezy) and earlier, see MPlayer for Breezy. Once you have set up and configured mplayer, add the plugin to Firefox by installing the mozilla-mplayer package.
Note: If your country's laws allow you to use w32codecs, installing that package is highly recommended. See the w32codecs section on the Restricted Formats wiki page for details.
How do I install other plugins?
See the wiki page for the media player you are interested in. The Restricted Formats wiki page offers a comprehensive discussion of proprietary multimedia file formats on (K)Ubuntu Linux. General information about installing other browser plugins is available at PluginDoc for Linux (x86).
Troubleshooting
How can I check which plugins are currently installed? - How can I verify that plugin x for Firefox is properly installed?
Enter about:plugins into the Firefox adress bar. You should now see a list of installed plugins along with some additional information (the plugin's file name, a brief description of its functionality and the associated MIME types).
The plugins page only shows me the name of the plugin. How can I make it show the plugin's location in the file system?
Enter about:config into the Firefox address bar. You will see a large list of configurable options for the Firefox browser. In the search bar, search for an entry named plugin.expose_full_path and set its value to true. Enter about:plugins into the browser adress bar. You should now see a list of installed plugins along with some additional information and their locations in the file system.
See also
Mozilla Plugin Support on Linux x86 and x86-64 platforms
Firefox distribution notes, Ubuntu Linux (x86)
The Restricted Formats wiki page
Multimedia Applications on Ubuntu Linux
Installing Free Java or Sun Java on Ubuntu Linux
MozillaZine Knowledge Base: Changing Media Handling Behaviour
A multimedia MIME type reference